1. The ball moves at a constant velocity and at approximately 0.8 seconds, the ball’s velocity increases, which is indicated by the increased spacing of the ball “footprint” model.
  2. Graph A is correct because the ball maintains a constant velocity which is indicated by the constant slope of the position vs. time graph. At around 0.8 seconds, the ball’s velocity increases, which is indicated by the increased slope of the position vs. time graph. Graph B is incorrect because the graph shows an increasing initial speed which is not true according to the ball model. Graph C is incorrect because the graph jumps. This would mean a teleportation occurred to suddenly appear farther away without any passed time between.
  3. Graph D is correct because the ball starts off with a constant velocity until around 0.8 seconds when the ball suddenly changes its velocity which is indicated by the jump or discontinuity in the velocity vs. time graph. Graph E is incorrect because the initial velocity, shows a gradual increase when the ball model indicates a constant velocity. Graph F is incorrect because the graph indicates that the ball accelerates to a new velocity but the ball model shows no indication of gradual acceleration since the spacing between the ball “footprints” suddenly changes.
©Kevin Trinh 2011